Restricted Exhaust System Check

Driveability comments like "lacks power under load" or "difficult to start, acts flooded and also lacks power" may indicate a restricted exhaust. In extreme cases the exhaust may be so restrictive that the engine will not start. Generally speaking, here's how to test for a restricted exhaust system:

• Attach a vacuum gauge to an intake manifold vacuum source.

• Allow the engine to reach operating temperature.

• From idle, raise engine speed to approximately 2000 rpm.

• Note: The vacuum reading should be close to normal idle reading.

• Next, quickly release the throttle.

Note: The vacuum reading should momentarily rise then smoothly drop back to a normal idle reading. If the vacuum rises slowly or does not quickly return to normal level, the exhaust system may be restricted.

If the catalyst has disintegrated, it is likely that contamination has also restricted the muffler. Don't overlook that possibility. If the engine will not start, try disconnecting the exhaust system at the manifold and see if the engine will start.

Lead Contamination Check

A common cause of converter contamination is lead poisoning. As mentioned, lead reduces converter efficiency by coating the catalyst element. Special lead detecting test paper (or paste) is available from aftermarket suppliers that checks for the presence of lead in the tailpipe. Follow the specific instructions provided by the test paper manufacturer.

Lead Contamination Check

A common cause of converter contamination is lead poisoning. As mentioned, lead reduces converter efficiency by coating the catalyst element. Special lead detecting test paper (or paste) is available from aftermarket suppliers that checks for the presence of lead in the tailpipe. Follow the specific instructions provided by the test paper manufacturer.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Responses

  • brenda
    How to test for ristricted exhaust?
    5 years ago

Post a comment